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Re: ANSI ASC X12: BIN and BDS segments
A sticky problem, but you have to consider it in this context: any
insertion of line break characters is completely outside of the X12
standard. If you're using an operating system, network protocol, or data
transfer protocol that does this, the receiver must be sure that it is
properly undone before trying to process the content of the binary data
element. But, that's going to be a problem with *any* data, and not just
binary data. The effects may not be as bad (random LF or CR characters
inserted rather than the translator getting lost while parsing), but the
data is still getting corrupted.
Mike
At 06:40 PM 3/23/2005 -0700, Kepa Zubeldia wrote:
>There is a little fly in the ointment...
>
>Even if you encode the content of the BIN/BDS payload in base64 or HEX or
>something easy to handle, you are likely to have the base64 encoded payload
>as individual "lines" instead of a long single stream. So, the communications
>protocols need to make sure they treat this delicate payload as "binary"
>instead of "text". It looks like lines of text, it apparently only contains
>printable characters...
>
>But each one of those base64-encoded lines ends with a \n or a \r\n depending
>on the system you are using. And, if the communication system changes the
>line endings from \n to \r\n or viceversa (e.g., FTP from unix to windows)
>then the actual byte count of the payload has changed and no longer matches
>the size of the payload that was explicitly stated in BIN01.
>
>So, even with the base64 encoding of the payload, these are rather fragile
>objects.
>
>One option could be to "require" base64 encoding and to ignore the BIN01
>value
>altogether, presuming the segment terminator will not be found in the base64
>encoded payload.
>
>Other options are left to the imagination of the system developers :-)
>
>Kepa Zubeldia
>Claredi
>
>
>
>On Wednesday 23 March 2005 02:23 pm, Michael Mattias wrote:
> >
> > From: "Mike Rawlins" <
> > > There's been a bit of traffic on this, but I don't think any of the
> > > messages have quite answered your essential questions. You ask:
> > >
> > > >But how can this be, given that a communications protocol may be a
> 7-bit
> > > >protocol? If you use a 7-bit protocol, either you'd lose
> > > >bit 7 of each octet or it would be misinterpreted as a control
> character.
> > > >Or, does the use of BDS/BIN presuppose the use of an 8-bit
> > > >protocol? Or preempt the use of high-order characters?
> > > >
> > > >Or does the standard just assume that "you have the data,
> communications
> > > >is a totally separate consideration?" (Which really seems
> > > >strange given the origin and original design of ANSI ASC X12 data
>format).
> >
> > > Actually, the answer is sort of the last case, but with
> > >qualification This is the reason for the "Filter ID Code" in BDS01 and
>EFI16 (used with BIN).
> >
> > Aha! Partners may (or may have to!) agree on an encoding standard for
>BIN03 data consistent with their communications agreement!
> >
> > Now *that* makes sense!! (If not to the little guys I work with, it
> does to
>me).
> >
> > Thank you much.
> >
> > Michael Mattias
> > Tal Systems, Inc.
> > Racine WI
> >
> > http://www.talsystems.com
> >
> >
> >
> >
> >
> >
> >
> > .
> > Please use the following Message Identifiers as your subject prefix:
><SALES>, <JOBS>, <LIST>, <TECH>, <MISC>, <EVENT>, <OFF-TOPIC>
> > Access the list online at: http://groups.yahoo.com/group/EDI-L
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
>
>--
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>
>.
>Please use the following Message Identifiers as your subject prefix:
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>
>
---------------------------------------------------------------
Michael C. Rawlins, Rawlins EC Consulting
www.rawlinsecconsulting.com
Using XML with Legacy Business Applications (Addison-Wesley, 2003)
www.awprofessional.com/titles/0321154940
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